Functional communication Training (FCT) is the most widely used treatment approach to address problem behavior exhibited by individuals with developmental disabilities. This strategy has been demonstrated to be effective in numerous published studies. However, little research has been conducted regarding the selection of the communication strategies included in such treatments and the manner in which antecedent stimuli, such as response prompts, are used when FCT is implemented. It is possible that communication strategy selected and the method by which it is prompted may affect the long-term maintenance of treatment gains, particularly when treatment integrity is challenged (e.g., treatment is not implemented as designed). Research related to response persistence (i.e., the continuation of a response when challenged) has demonstrated that response-reinforcer variables such as the rate of reinforcement will influence it. These effects have been demonstrated in the basic [behavioral momentum theory] literature and in the applied literature with respect to the response persistence of problem behavior. What is less well understood is how other types of variables, such as response-response variables and stimulus-response variables, will affect response persistence and, in particular, the response persistence of appropriate behavior such as communication. Clinically, it is important that we design treatments that not only result in the reduction of problem behavior and the development of appropriate strategies to obtain reinforcers, but that also produce appropriate behavior that is resilient in the face of challenges to treatment. The proposed studies will provide more information regarding how to select the communication strategy that will persist longest when challenged and how to structure at least one antecedent component of the treatment (response prompting) to facilitate response persistence.